What is CVE-2026-33186?

CVE-2026-33186 is a critical-severity vulnerability in Grpc Grpc-go, classified under Improper Authorization. CVSS score: 9.1/10. Published 2026-03-20.

How severe is CVE-2026-33186?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Is CVE-2026-33186 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Auth bypass in Grpc Grpc-go

CVE-2026-33186

gRPC-Go is the Go language implementation of gRPC. Versions prior to 1.79.3 have an authorization bypass resulting from improper input validation of the HTTP/2 `:path` pseudo-header. The gRPC-Go server was too lenient in its routing logic…

EPSS: 0.000 (5.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

Affected products

Grpc Grpc-go — versions < 1.79.3

Weakness classification (CWE)

CWE-285 — Improper Authorization

Public proof-of-concept exploits

JohannesLks/CVE-2026-33186

References

https://github.com/grpc/grpc-go/security/advisories/GHSA-p77j-4mvh-x3m3 (x_refsource_CONFIRM)

Frequently asked questions

What is CVE-2026-33186?: CVE-2026-33186 is a critical-severity vulnerability in Grpc Grpc-go, classified under Improper Authorization. CVSS score: 9.1/10. Published 2026-03-20.
How severe is CVE-2026-33186?: Critical severity. CVSS v3 base score is 9.1 out of 10.
Is CVE-2026-33186 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.